The present invention is generally related to seismic data processing, and more particularly to seismic data processing of data from a plurality of sensors for purposes such as monitoring hydraulic fracturing treatments. Seismic data processing has long been associated with the exploration and development of subterranean resources such as hydrocarbon reservoirs. While numerous technological advances have been made in the art, at least some potentially useful seismic data is not fully utilized because of unfavorable signal to noise ratios.
One example of a procedure that could be enhanced by improved seismic data processing is Hydraulic fracture monitoring (HFM). Hydraulic fracturing is a stimulation treatment via which reservoir permeability is improved by subjecting a formation adjacent to a portion of a borehole to increased pressure in order to create and widen fractures in the formation, thereby improving oil and gas recovery. HFM techniques are utilized to evaluate the propagation paths and thickness of the fractures. Some HFM techniques that are known in the art are described in: R. D. Barree, “Application of pre-frac injection/falloff tests in fissured reservoirs field examples,” SPE paper 39932, presented at the 1998 SPE Rocky Mountain Regional Conference, Denver, Apr. 5-8, 1998; C. L. Cipolla and C. A. Wright, “State-of-the-art in hydraulic fracture diagnostics,” SPE paper 64434, presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition held in Brisbane, Australia, October 1618, 2000; C. A. Wright et. al, “Downhole tiltmeter fracture mapping: A new tool for directly measuring hydraulic fracture dimensions,” SPE paper 49193, Presented at 1998 SPE Annual Technical Conference, New Orleans, 1998; C. A. Wright et. al, “Surface tiltmeter fracture mapping reaches new depths 10,000 feet, and beyond,” SPE paper 39919, presented at the 1998 SPE Rocky Mountain Regional Conference, Denver, Apr. 5-8, 1998; N. R. Warpinski et. al, “Mapping hydraulic fracture growth and geometry using microseismic events detected by a wireline retrievable accelerometer array,” SPE 40014 presented at the 1998 SPE Gas Technology Symposium in Calgary, Canada, Mar. 15-16, 1998; R. L. Johnson Jr. and R. A. Woodroof Jr., “The application of hydraulic fracturing models in conjunction with tracer surveys to characterize and optimize fracture treatments in the brushy canyon formation, southeastern new mexico,” SPE paper 36470, presented at the 1996 Annual Technical Conference and Exhibition, Denver, Oct. 6-9, 1996; J. T. Rutledge and W. S. Phillips, “Hydraulic stimulation of natural fractures as revealed by induced microearthquakes, carthage cotton valley gas field, east texas,” Geophysics, 68:441-452, 2003; and N. R. Warpinski, S. L. Wolhart, and C. A. Wright, “Analysis and prediction of microseismicity induced by hydraulic fracturing,” SPE Journal, pages 24-33, March 2004. The last two references listed above describe “microseismic” techniques. Microseismic events occur during hydraulic fracture treatment when pre-existing planes of weakness in the reservoir and surrounding layers undergo shear slippage due to changes in stress and pore pressure. The resulting microseismic waves can be recorded by arrays of multicomponent geophones placed in the well undergoing treatment or a nearby monitoring well. However, the recorded microseismic waveforms are usually complex wavetrains containing high amplitude noise as well as borehole waves excited by operation of pumps located at the surface. Consequently, accurately estimating the time of arrival of various recorded events such as p- and s-wave arrivals is technologically challenging.